Calculating Scale, a Substitute for the Slide Rule

Abstract

IN this book the author provides and explains then use of two graduated scales, placed adjacent to each other for comparison and fixed together, on one of which numbers can be read off, and on the other the logarithms of the numbers, or vice versâ. This compound scale is 100 inches long, and is cut up into twenty lengths, printed in successive columns, and occupies four pages of the book. This comparatively great length enables three significant figures to be read off directly from the scale divisions and subdivisions, while a fourth figure can be estimated. The author claims that computations can be -made with a degree of accuracy equal to that obtained by the use of four-figure log tables, and with less trouble. We suspect, however, that few would be found who would allow this claim, or be willing to give up their tables for the author's plan. The. title of the book is somewhat misleading; instead of a “substitute for the slide rule,” the proper description would be, a substitute for tables of logarithms; the “calculating scale” is only an equivalent for the slide rule in the sense that a log table may be so regarded. We fail to see any useful purpose that this scale is likely to serve.

Calculating Scale, a Substitute for the Slide Rule.

By W. Knowles Pp. 29. (London: E. and F. N. Spon, Ltd.; New York: Spon and Chamberlain, 1903.) Price 1s. net.